Genetic testing

During your pregnancy you’ll have several tests that let you hear your baby’s heartbeat, ensure he or she is growing at the right pace and even help you zero in on your due date.

Genetic tests can provide you with information about any changes in your baby’s genes or chromosomes that may indicate a serious genetic disorder before he or she is born. Importantly, genetic testing is a personal decision — you and your partner should discuss whether these tests are right for you.

Who is genetic testing right for?

Genetic testing is typically optional for any pregnancy. Many pregnant women choose genetic tests because they want to know whether their babies are developing properly during pregnancy.

However, your provider may suggest certain genetic tests if you have a high-risk pregnancy. Your pregnancy may be considered high-risk if you:

Are under 17 or over 35

Are pregnant with twins or multiples

Have a history of inherited disease

Have had pregnancy complications in the past

What happens during a genetic test?

Most often, pregnant women undergo genetic screening tests, which can help tell them if their baby is at high risk for having a genetic disorder.

A screening typically consists of a blood test. An ultrasound may also be done the same day to improve the accuracy of the screening. Genetic screenings cannot identify all birth defects, and a screening does not provide a definitive diagnosis of a genetic disorder. If a screening result is abnormal, you’ll be referred to Geisinger’s Maternal-Fetal Medicine Department for further testing.

When are screenings done?

Genetic screening tests can be done at two times during your pregnancy — a test between weeks 11 and 14 is called a first trimester screening, and a test between weeks 15 and 22 is called a quad screening. For genetic screening tests to provide accurate results, it’s important to know when your baby was conceived.

What types of screenings can be done?

Genetic tests can screen for a number of disorders. The most common include:

Down syndrome (trisomy 21) – Down syndrome happens when a person has an extra chromosome 21. Down syndrome can cause mental disabilities and heart defects. Women over 35 are at a higher risk for having a baby with Down syndrome.

Edwards syndrome (trisomy 18) – Edwards syndrome happens when a person has an extra chromosome 18. Edwards syndrome can cause serious health issues, such as poor growth and brain and heart defects, and can lead to stillbirth or death in infancy.

Patau syndrome (trisomy 13) – Patau syndrome happens when a person has an extra chromosome 13. Patau syndrome causes serious health issues, often resulting in stillbirth or death within a few days of birth.

Spina bifida – Spina bifida, also called a neural tube defect, happens when a baby’s spinal cord does not develop properly. Spina bifida can cause minor health issues, such as bowel and bladder problems, or more serious issues, such as trouble walking.

Cystic fibrosis – Cystic fibrosis causes lung and pancreas secretions to become sticky, which can result in problems breathing and absorbing nutrients over time.

The different types of screenings may differ depending on when they occur during pregnancy. If you’re considering genetic screening, talk to your provider early in your pregnancy to weigh your options so you can make the best decision for you and your family.

Pregnancy Guide

This book will guide you through your pregnancy — from body changes and what your baby is doing at each stage of your pregnancy to how to prepare for labor and take care of yourself after delivery.